KVM: arm64: Add helper vgic_write_guest_lock()

Currently, the unknown no-running-vcpu sites are reported when a
dirty page is tracked by mark_page_dirty_in_slot(). Until now, the
only known no-running-vcpu site is saving vgic/its tables through
KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_SAVE_TABLES} command on KVM device
"kvm-arm-vgic-its". Unfortunately, there are more unknown sites to
be handled and no-running-vcpu context will be allowed in these
sites: (1) KVM_DEV_ARM_{VGIC_GRP_CTRL, ITS_RESTORE_TABLES} command
on KVM device "kvm-arm-vgic-its" to restore vgic/its tables. The
vgic3 LPI pending status could be restored. (2) Save vgic3 pending
table through KVM_DEV_ARM_{VGIC_GRP_CTRL, VGIC_SAVE_PENDING_TABLES}
command on KVM device "kvm-arm-vgic-v3".

In order to handle those unknown cases, we need a unified helper
vgic_write_guest_lock(). struct vgic_dist::save_its_tables_in_progress
is also renamed to struct vgic_dist::save_tables_in_progress.

No functional change intended.

Suggested-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230126235451.469087-3-gshan@redhat.com

arch/arm64/kvm/vgic/vgic-its.c

@@ -2187,7 +2187,7 @@ static int vgic_its_save_ite(struct vgic_its *its, struct its_device *dev,
 	       ((u64)ite->irq->intid << KVM_ITS_ITE_PINTID_SHIFT) |
 		ite->collection->collection_id;
 	val = cpu_to_le64(val);
-	return kvm_write_guest_lock(kvm, gpa, &val, ite_esz);
+	return vgic_write_guest_lock(kvm, gpa, &val, ite_esz);
 }
 
 /**
@@ -2339,7 +2339,7 @@ static int vgic_its_save_dte(struct vgic_its *its, struct its_device *dev,
 	       (itt_addr_field << KVM_ITS_DTE_ITTADDR_SHIFT) |
 		(dev->num_eventid_bits - 1));
 	val = cpu_to_le64(val);
-	return kvm_write_guest_lock(kvm, ptr, &val, dte_esz);
+	return vgic_write_guest_lock(kvm, ptr, &val, dte_esz);
 }
 
 /**
@@ -2526,7 +2526,7 @@ static int vgic_its_save_cte(struct vgic_its *its,
 	       ((u64)collection->target_addr << KVM_ITS_CTE_RDBASE_SHIFT) |
 	       collection->collection_id);
 	val = cpu_to_le64(val);
-	return kvm_write_guest_lock(its->dev->kvm, gpa, &val, esz);
+	return vgic_write_guest_lock(its->dev->kvm, gpa, &val, esz);
 }
 
 /*
@@ -2607,7 +2607,7 @@ static int vgic_its_save_collection_table(struct vgic_its *its)
 	 */
 	val = 0;
 	BUG_ON(cte_esz > sizeof(val));
-	ret = kvm_write_guest_lock(its->dev->kvm, gpa, &val, cte_esz);
+	ret = vgic_write_guest_lock(its->dev->kvm, gpa, &val, cte_esz);
 	return ret;
 }
 
@@ -2743,7 +2743,6 @@ static int vgic_its_has_attr(struct kvm_device *dev,
 static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr)
 {
 	const struct vgic_its_abi *abi = vgic_its_get_abi(its);
-	struct vgic_dist *dist = &kvm->arch.vgic;
 	int ret = 0;
 
 	if (attr == KVM_DEV_ARM_VGIC_CTRL_INIT) /* Nothing to do */
@@ -2763,9 +2762,7 @@ static int vgic_its_ctrl(struct kvm *kvm, struct vgic_its *its, u64 attr)
 		vgic_its_reset(kvm, its);
 		break;
 	case KVM_DEV_ARM_ITS_SAVE_TABLES:
-		dist->save_its_tables_in_progress = true;
 		ret = abi->save_tables(its);
-		dist->save_its_tables_in_progress = false;
 		break;
 	case KVM_DEV_ARM_ITS_RESTORE_TABLES:
 		ret = abi->restore_tables(its);
@@ -2792,7 +2789,7 @@ bool kvm_arch_allow_write_without_running_vcpu(struct kvm *kvm)
 {
 	struct vgic_dist *dist = &kvm->arch.vgic;
 
-	return dist->save_its_tables_in_progress;
+	return dist->table_write_in_progress;
 }
 
 static int vgic_its_set_attr(struct kvm_device *dev,

arch/arm64/kvm/vgic/vgic.h

@@ -6,6 +6,7 @@
 #define __KVM_ARM_VGIC_NEW_H__
 
 #include <linux/irqchip/arm-gic-common.h>
+#include <asm/kvm_mmu.h>
 
 #define PRODUCT_ID_KVM		0x4b	/* ASCII code K */
 #define IMPLEMENTER_ARM		0x43b
@@ -131,6 +132,19 @@ static inline bool vgic_irq_is_multi_sgi(struct vgic_irq *irq)
 	return vgic_irq_get_lr_count(irq) > 1;
 }
 
+static inline int vgic_write_guest_lock(struct kvm *kvm, gpa_t gpa,
+					const void *data, unsigned long len)
+{
+	struct vgic_dist *dist = &kvm->arch.vgic;
+	int ret;
+
+	dist->table_write_in_progress = true;
+	ret = kvm_write_guest_lock(kvm, gpa, data, len);
+	dist->table_write_in_progress = false;
+
+	return ret;
+}
+
 /*
  * This struct provides an intermediate representation of the fields contained
  * in the GICH_VMCR and ICH_VMCR registers, such that code exporting the GIC

include/kvm/arm_vgic.h

@@ -263,7 +263,7 @@ struct vgic_dist {
 	struct vgic_io_device	dist_iodev;
 
 	bool			has_its;
-	bool			save_its_tables_in_progress;
+	bool			table_write_in_progress;
 
 	/*
 	 * Contains the attributes and gpa of the LPI configuration table.